The invention relates in general to vibratory electrical tools, more particularly, to an actuator for a portable electric vibratory device providing in-line motion for sanding, polishing, cleaning and like applications.
The prior art disclosed in the U.S. Pat. Nos. 3,083,508, 2,790,276, and 2,764,703, disclose in-line sanders actuated by solenoid type electromagnetic motors. These devices have been found to be extremely noisy in operation, and also having limited power potential in that any pressure applied to a sanding or polishing platen will quickly restrict motion of the platen thereby obviating use of the device.
The prior art also discloses, in U.S. Pat. Nos. 2,893,174 and 2,830,411, sanding or polishing platens which are reciprocated or orbited by rotating electric motors which extend normally to the surface to be operated upon, thereby creating a somewhat bulky apparatus, the use of which tends to be awkward.
Optimumly, the in-line sander, which is a finish sanding machine simulating the operation of hand sanding, is most advantageously implemented by a device which may be gripped in the palm of a single hand. A U.S. Pat. No. 2,545,942 discloses a small sanding machine which may be held in the palm of a hand for maximum utility. This device, however, utilizes a horizontally oriented rotating electric motor to implement an orbital motion of a sanding or polishing platen. This motion is implemented through two sets of bevel gearing on opposite ends of the motor shaft which drive auxiliary shafts having crank connections to the sanding platen. Aside from not having the desired in-line motion, this device also utilizes more expensive bevel gears and two auxiliary shafts, resulting in an expensive construction.
What is required is a new form of actuator which might be used with a horizontally oriented motor in a minimum amount of space and at the least expenditure so that the power superiority of the rotating electric motor may be economically taken advantage of.